The load for external reference should be a full pointer load
instead of tagged size.

Change-Id: I3460a26abea5053ba6daa5c6ed908cb93431654a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3842348Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Junliang Yan <junyan@redhat.com>
Cr-Commit-Position: refs/heads/main@{#82625}